Faint high-latitude carbon stars discovered by the sloan digital sky survey

Methods and initial results

Bruce Margon, Scott F. Anderson, Hugh C. Harris, Michael A. Strauss, G. R. Knapp, Xiaohui Fan, Donald P. Schneider, Daniel E. Vanden Berk, David J. Schlegel, Eric W. Deutsch, Željko Ivezić, Patricke B. Hall, Benjamin F. Williams, Arthur F. Davidsen, J. Brinkmann, I. Csabai, Jeffrey J E Hayes, Greg Hennessy, Ellyne K. Kinney, S. J. Kleinman & 7 others Don Q. Lamb, Dan Long, Eric H. Neilsen, Robert Nichol, Atsuko Nitta, Stephanie A. Snedden, Donald G. York

Research output: Contribution to journalArticle

50 Citations (Scopus)

Abstract

We report the discovery of 39 faint high-latitude carbon stars (FHLCs) from Sloan Digital Sky Survey (SDSS) commissioning data. The objects, each selected photometrically and verified spectroscopically, range over 16.6 <r* <20.0 and show a diversity of temperatures as judged by both colors and NaD line strengths. Although a handful of these stars were previously known, these objects are, in general, too faint and too warm to be effectively identified in other modern surveys such as the Two Micron All Sky Survey, nor are their red/near-IR colors particularly distinctive. The implied surface density of FHLCs in this magnitude range is uncertain at this preliminary stage of the survey because of completeness corrections but is clearly greater than 0.05 deg-2. At the completion of the Sloan survey, there will be many hundred homogeneously selected and observed FHLCs in this sample. We present proper-motion measures for each object, indicating that the sample is a mixture of extremely distant (greater than 100 kpc) halo giant stars, useful for constraining halo dynamics, and members of the recently recognized exotic class of very nearby dwarf carbon (dC) stars. The broadband colors of the two populations are indistinguishable. Motions, and thus dC classification, are inferred for 40%-50% of the sample, depending on the level of statistical significance invoked. The new list of dC stars presented here, although selected from only a small fraction of the final SDSS, doubles the number of such objects found by all previous methods. The observed kinematics suggest that the dwarfs occupy distinct halo and disk populations. The coolest FHLCs with detectable proper motions in our sample also display multiple CaH bands in their spectra. It may be that CaH is another long-sought, low-resolution, spectroscopic luminosity discriminant between dC's and distant faint giants, at least for the cooler stars.

Original languageEnglish
Pages (from-to)1651-1669
Number of pages19
JournalAstronomical Journal
Volume124
Issue number3 1761
DOIs
Publication statusPublished - Sep 2002

Fingerprint

carbon stars
survey method
polar regions
carbon
dwarf stars
halos
proper motion
color
stars
giant stars
completeness
coolers
lists
kinematics
luminosity
broadband

Keywords

  • Astrometry
  • Stars: carbon
  • Stars: statistics
  • Surveys

ASJC Scopus subject areas

  • Space and Planetary Science
  • Astronomy and Astrophysics

Cite this

Margon, B., Anderson, S. F., Harris, H. C., Strauss, M. A., Knapp, G. R., Fan, X., ... York, D. G. (2002). Faint high-latitude carbon stars discovered by the sloan digital sky survey: Methods and initial results. Astronomical Journal, 124(3 1761), 1651-1669. https://doi.org/10.1086/342284

Faint high-latitude carbon stars discovered by the sloan digital sky survey : Methods and initial results. / Margon, Bruce; Anderson, Scott F.; Harris, Hugh C.; Strauss, Michael A.; Knapp, G. R.; Fan, Xiaohui; Schneider, Donald P.; Vanden Berk, Daniel E.; Schlegel, David J.; Deutsch, Eric W.; Ivezić, Željko; Hall, Patricke B.; Williams, Benjamin F.; Davidsen, Arthur F.; Brinkmann, J.; Csabai, I.; Hayes, Jeffrey J E; Hennessy, Greg; Kinney, Ellyne K.; Kleinman, S. J.; Lamb, Don Q.; Long, Dan; Neilsen, Eric H.; Nichol, Robert; Nitta, Atsuko; Snedden, Stephanie A.; York, Donald G.

In: Astronomical Journal, Vol. 124, No. 3 1761, 09.2002, p. 1651-1669.

Research output: Contribution to journalArticle

Margon, B, Anderson, SF, Harris, HC, Strauss, MA, Knapp, GR, Fan, X, Schneider, DP, Vanden Berk, DE, Schlegel, DJ, Deutsch, EW, Ivezić, Ž, Hall, PB, Williams, BF, Davidsen, AF, Brinkmann, J, Csabai, I, Hayes, JJE, Hennessy, G, Kinney, EK, Kleinman, SJ, Lamb, DQ, Long, D, Neilsen, EH, Nichol, R, Nitta, A, Snedden, SA & York, DG 2002, 'Faint high-latitude carbon stars discovered by the sloan digital sky survey: Methods and initial results', Astronomical Journal, vol. 124, no. 3 1761, pp. 1651-1669. https://doi.org/10.1086/342284
Margon B, Anderson SF, Harris HC, Strauss MA, Knapp GR, Fan X et al. Faint high-latitude carbon stars discovered by the sloan digital sky survey: Methods and initial results. Astronomical Journal. 2002 Sep;124(3 1761):1651-1669. https://doi.org/10.1086/342284
Margon, Bruce ; Anderson, Scott F. ; Harris, Hugh C. ; Strauss, Michael A. ; Knapp, G. R. ; Fan, Xiaohui ; Schneider, Donald P. ; Vanden Berk, Daniel E. ; Schlegel, David J. ; Deutsch, Eric W. ; Ivezić, Željko ; Hall, Patricke B. ; Williams, Benjamin F. ; Davidsen, Arthur F. ; Brinkmann, J. ; Csabai, I. ; Hayes, Jeffrey J E ; Hennessy, Greg ; Kinney, Ellyne K. ; Kleinman, S. J. ; Lamb, Don Q. ; Long, Dan ; Neilsen, Eric H. ; Nichol, Robert ; Nitta, Atsuko ; Snedden, Stephanie A. ; York, Donald G. / Faint high-latitude carbon stars discovered by the sloan digital sky survey : Methods and initial results. In: Astronomical Journal. 2002 ; Vol. 124, No. 3 1761. pp. 1651-1669.
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abstract = "We report the discovery of 39 faint high-latitude carbon stars (FHLCs) from Sloan Digital Sky Survey (SDSS) commissioning data. The objects, each selected photometrically and verified spectroscopically, range over 16.6 -2. At the completion of the Sloan survey, there will be many hundred homogeneously selected and observed FHLCs in this sample. We present proper-motion measures for each object, indicating that the sample is a mixture of extremely distant (greater than 100 kpc) halo giant stars, useful for constraining halo dynamics, and members of the recently recognized exotic class of very nearby dwarf carbon (dC) stars. The broadband colors of the two populations are indistinguishable. Motions, and thus dC classification, are inferred for 40{\%}-50{\%} of the sample, depending on the level of statistical significance invoked. The new list of dC stars presented here, although selected from only a small fraction of the final SDSS, doubles the number of such objects found by all previous methods. The observed kinematics suggest that the dwarfs occupy distinct halo and disk populations. The coolest FHLCs with detectable proper motions in our sample also display multiple CaH bands in their spectra. It may be that CaH is another long-sought, low-resolution, spectroscopic luminosity discriminant between dC's and distant faint giants, at least for the cooler stars.",
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T1 - Faint high-latitude carbon stars discovered by the sloan digital sky survey

T2 - Methods and initial results

AU - Margon, Bruce

AU - Anderson, Scott F.

AU - Harris, Hugh C.

AU - Strauss, Michael A.

AU - Knapp, G. R.

AU - Fan, Xiaohui

AU - Schneider, Donald P.

AU - Vanden Berk, Daniel E.

AU - Schlegel, David J.

AU - Deutsch, Eric W.

AU - Ivezić, Željko

AU - Hall, Patricke B.

AU - Williams, Benjamin F.

AU - Davidsen, Arthur F.

AU - Brinkmann, J.

AU - Csabai, I.

AU - Hayes, Jeffrey J E

AU - Hennessy, Greg

AU - Kinney, Ellyne K.

AU - Kleinman, S. J.

AU - Lamb, Don Q.

AU - Long, Dan

AU - Neilsen, Eric H.

AU - Nichol, Robert

AU - Nitta, Atsuko

AU - Snedden, Stephanie A.

AU - York, Donald G.

PY - 2002/9

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N2 - We report the discovery of 39 faint high-latitude carbon stars (FHLCs) from Sloan Digital Sky Survey (SDSS) commissioning data. The objects, each selected photometrically and verified spectroscopically, range over 16.6 -2. At the completion of the Sloan survey, there will be many hundred homogeneously selected and observed FHLCs in this sample. We present proper-motion measures for each object, indicating that the sample is a mixture of extremely distant (greater than 100 kpc) halo giant stars, useful for constraining halo dynamics, and members of the recently recognized exotic class of very nearby dwarf carbon (dC) stars. The broadband colors of the two populations are indistinguishable. Motions, and thus dC classification, are inferred for 40%-50% of the sample, depending on the level of statistical significance invoked. The new list of dC stars presented here, although selected from only a small fraction of the final SDSS, doubles the number of such objects found by all previous methods. The observed kinematics suggest that the dwarfs occupy distinct halo and disk populations. The coolest FHLCs with detectable proper motions in our sample also display multiple CaH bands in their spectra. It may be that CaH is another long-sought, low-resolution, spectroscopic luminosity discriminant between dC's and distant faint giants, at least for the cooler stars.

AB - We report the discovery of 39 faint high-latitude carbon stars (FHLCs) from Sloan Digital Sky Survey (SDSS) commissioning data. The objects, each selected photometrically and verified spectroscopically, range over 16.6 -2. At the completion of the Sloan survey, there will be many hundred homogeneously selected and observed FHLCs in this sample. We present proper-motion measures for each object, indicating that the sample is a mixture of extremely distant (greater than 100 kpc) halo giant stars, useful for constraining halo dynamics, and members of the recently recognized exotic class of very nearby dwarf carbon (dC) stars. The broadband colors of the two populations are indistinguishable. Motions, and thus dC classification, are inferred for 40%-50% of the sample, depending on the level of statistical significance invoked. The new list of dC stars presented here, although selected from only a small fraction of the final SDSS, doubles the number of such objects found by all previous methods. The observed kinematics suggest that the dwarfs occupy distinct halo and disk populations. The coolest FHLCs with detectable proper motions in our sample also display multiple CaH bands in their spectra. It may be that CaH is another long-sought, low-resolution, spectroscopic luminosity discriminant between dC's and distant faint giants, at least for the cooler stars.

KW - Astrometry

KW - Stars: carbon

KW - Stars: statistics

KW - Surveys

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